1. Field of the Invention
The present invention relates to liquid ejecting apparatuses provided with a moving unit that moves when it receives a moving force, and a plurality of nozzle rows for ejecting liquid onto a medium, and with which it is possible to adjust the positions of the nozzle rows on the moving unit, and methods for adjusting the positions of those nozzle rows.
2. Description of the Related Art
In recent years, inkjet printers that eject ink as a liquid have become particularly popular as liquid ejecting apparatuses for ejecting liquid from nozzle rows (made of numerous nozzles arranged in lines) onto a medium. These inkjet printers are provided with a print head provided with a plurality of nozzle rows, and a carriage that is for holding the print head and that is capable of moving back and forth in a main-scanning direction. Print paper, serving as a medium, is fed intermittently in a sub-scanning direction, which is perpendicular to the main-scanning direction, and during the pauses in this feeding, the carriage is moved in the main-scanning direction and ink droplets are ejected from the nozzle rows toward the print paper so as to form numerous dot rows (numerous rows of dots, which are formed by ink droplets that have landed, arranged in straight lines). The paper feeding and movement of the carriage are repeated in alternation, forming a predetermined print image on the print paper. There has been increased diversity in the type of such inkjet printers in recent years, and for example, large-size inkjet printers in which a plurality of print heads are provided adjacent each other in the carriage so as to allow large size paper, such as A0 size paper, to be printed have also become available.
The print image formed by such inkjet printers is made of numerous dot rows formed by ejecting droplets of ink from the nozzle rows. Therefore, if the positions where dot rows are formed, which are the positions where the ink droplets land on the print paper, deviate from expected design positions, then an attractive print image cannot be printed on the print paper. In particular, in the case of a large-size inkjet printer provided with a plurality of print heads as described above, if the positions of the nozzle rows are not consistent among the plurality of print heads on the carriage, then there will be a lack of coordination in the positions where the dot rows are formed among the print heads, and if all of the print heads are used to draw a single print image, then an attractive print image cannot be obtained.
Consequently, with regard to such large-size printers, a printer that allows the positions of the print heads on the carriage to be adjusted individually has been proposed (for example, Japanese Patent Application Laid-open Publication No. 9-262992). With such a configuration, by appropriately moving each print head in the main-scanning direction or the sub-scanning direction, the positions of the nozzle rows on the carriage are coordinated, i.e., adjusted for suitable arrangement.
The publication above, however, does not disclose which print head, among the plurality of print heads on the carriage, should be taken as a reference when adjusting the positions. Thus, if the print head that is taken as the reference is prone to vibration during carriage movement, the positions where dot rows are formed by the reference print head will fluctuate, and it is difficult to coordinate the dot-row formation positions among the print heads even if the positions of the other print heads are precisely adjusted with respect to the reference. As a result, an attractive print image cannot be obtained.